Field of the Invention
The present invention relates to methods of cutting and mounting soft parts and apparatuses for cutting and mounting soft parts and, more particularly, to methods and apparatuses for cutting a sheet material formed by adhering a double-coated tape with a release sheet to a porous soft member into a predetermined shape, separating the cut sheet material from the release sheet, and adhering the separated sheet material to an article.
Conventionally, various methods and apparatuses have been proposed to cut a sheet material, which is continuously formed by adhering it to one surface of a porous soft material via a double-coated tape as an adhesive layer to be temporarily adhered to a release sheet, into a predetermined shape on the release sheet, and separate the cut sheet material from the release sheet.
FIG. 32 is a view showing the principle of operation of "a method and an apparatus for cutting a gel member" disclosed in Japanese Patent Laid-Open No. 8-150600 so that the view is close to the arrangement of the present invention. Referring to FIG. 32, a horn 1006 is fixed to an ultrasonic generating means, and a self-adhesive gel pad 1001 is arranged on a work surface 1006a of the horn 1006 via a contact plate 1002. A cutting blade 1011 having a predetermined shape is arranged on this self-adhesive gel pad 1001. While the cutting blade 1011 is moved to a position indicated by the broken lines, ultrasonic vibration is applied to the horn 1006 and the cutting blade 1011. Consequently, the material is cut into a predetermined shape while being prevented from sticking to the blade.
This prior art can cut a material which is difficult to cut. However, since the gel pad is positioned in a portion surrounded by the cutting blade after cutting, it is difficult to extract the gel pad. This makes handling of the apparatus very difficult. Therefore, it is difficult to successively automate the cutting step and its subsequent steps.
Accordingly, the steps of cutting and separating a sheet material from the release sheet (and pasting a soft part 1) are commonly separated. That is, a sheet material supplied from a reel on which the material is wound is cut by a hydraulic or air-pressure press apparatus having an output of a few tons, which is also a cutting apparatus incorporating a cutting blade (mold) primarily using a Thomson blade or a soft part blade. The sheet material is full-cut together with a release sheet or half-cut so that the release sheet is left uncut into a predetermined shape by force cutting by the cutting apparatus, thereby obtaining a soft part punched into the predetermined shape. Thereafter, the soft part is manually separated from the release sheet and manually pasted on a work as an object.
On the other hand, a porous elastic member such as urethane foam is difficult to accurately cut into a predetermined shape because of its softness.
It is, therefore, being demanded to develop a method and an apparatus capable of operating with high productivity for the technique of cutting a sheet material, which is formed by adhering an elastic member such as urethane foam onto a base member such as paper via an adhesive layer, into a predetermined shape.
An elastic member with softness such as urethane foam is used as a soft part 1 of a vessel, and it is being demanded to develop a technique of cutting the elastic member 1 into a complicated shape combining curves of the soft part of the vessel.
Unfortunately, the above prior art has the following problems.
Especially when the sheet material is a porous soft (elastic) member, the shape of the sheet material deforms by sheet compression by the cutting blade if force cutting is performed by the press apparatus and the cutting blade. Consequently, the shapes after the cutting vary to result in low cutting accuracy. Especially when the sheet material is half-cut to leave the release sheet uncut, the cutting depth changes in accordance with slight differences in thickness between sheet materials resulting from lot differences or with cutting blade conditions (e.g., wear of the blade edge, adhesion of the self-adhesive to the blade, and a change in the mounting position of the blade caused by replacement). As a consequence, the sheet material is left uncut, or the release sheet is undesirably cut. Accordingly, it is necessary to frequently slightly adjust the cutting depth.
Since the output of the press apparatus is very high, i.e., several tons are necessary, the size, cost, and installation space of the apparatus are increased.
Also, a soft part is manually separated from the release sheet and manually pasted as described previously. Therefore, it is difficult to totally automate a series of cutting, separating, and pasting steps. This results in low productivity and the difficulties of stabilizing the quality and performing continuous production. Human intervention naturally produces variations in the accuracy of pasting position to an article and the pasted state, so an accuracy limit is pointed out.